It is well-known that diseases of the cardiovascular system affect millions of people each year and are a leading cause of death in the United States and throughout the world. One form of cardiovascular disease is ischemia, in which there is a reduction in the blood supply leading to the heart. This reduction is caused by atherosclerosis or any other condition that creates a restriction in blood flow at a critical point in the cardiovascular system that supplies blood to the heart. For some patients, the blockage or restriction in the blood flow can be surgically treated by coronary artery bypass grafting (CABG), commonly referred to as a “coronary bypass” operation. In this procedure, the surgeon removes a portion of a vein or artery from another part of the body and uses it as a graft to bypass the obstruction and restore circulation to the heart.
The surgeon uses the graft to bypass the obstruction by attaching one end to the ascending aorta and attaching the other end to a coronary artery, distal to the obstruction. The procedure of making these attachments is known as an anastomosis. This can be performed with the heart stopped and the patient put on cardiopulmonary bypass or, during a beating-heart CABG procedure, while the heart muscle is continuing to contract and pump blood. However, in the latter case, the anastomosis is difficult to perform because the heart is moving and pumping blood at the same time that the surgeon is suturing the graft in place.
Importantly, the sutures must be carefully placed so that the graft is firmly attached and does not leak when blood flow through the graft is established. During a beating-heart CABG, it is important that the procedure be performed rapidly because the blood flow through the target coronary artery may be interrupted or reduced during the procedure in order to create the anastomosis without excessive blood loss. Moreover, if the beating heart CABG procedure is performed partially or completely in a minimally invasive manner, the working space and visual access may be limited because the surgeon may be working through a small incision in the chest or may be viewing the procedure on a video monitor if the site of the surgery is viewed via a surgical scope.